The invention relates generally to the field of fuel injectors. In particular, this invention relates to a method for maintaining the proper alignment of a fuel injector with a fuel intake port utilizing a retaining clip.
In modern multi-valve engines utilizing fuel injectors to supply fuel to intake ports, it is important to maintain the proper alignment between the fuel injectors and the corresponding intake ports. In multi-valve engines, it is important to maintain rotational alignment and reduce axial movement of the fuel injector. If a fuel injector is not properly aligned with an intake port, wall wetting can result. Wall wetting occurs when the fuel spray plume from the fuel injector is off-center, and some of the spray contacts the walls of the intake port. This results in reduced performance of the engine and adversely affected emissions. During the shipping process, fuel injectors are subjected to forces that can cause them to rotate and in some cases, even become dislodged from the fuel rails. To combat this problem, retaining clips were used when shipping fuel delivery systems containing fuel injectors.
These retaining clips were utilized as dunnage devices. The clips were attached at the interface between the fuel rails and the fuel injectors to prevent the fuel injectors from coming loose from the fuel rail cups during shipping. Early clips consisted of stamped metal pieces that were loosely fitted around the neck of the fuel injector. The clips had a number of upstanding protrusions providing bias towards the fuel rail cup and applying pressure thereon, keeping the injector attached to the fuel rail cup during shipping.
While this method prevented the injector from becoming dislodged and prevented some shifting, these early clips did not significantly prevent rotational movement of the injector in relation to the fuel rail cup during shipping. The clips were eventually improved to include an anti-rotation feature consisting of a tang positioned to interfere with the rotation of the fuel injector. The upstanding protrusions made contact with the fuel rail cup, and the anti-rotation tang extended in a direction towards the fuel rail to align with a slot on the fuel rail cup. This retainer was loosely fit to the injector and the fuel rail cup, and allowed slight rotation of the components until the anti-rotation tang came in contact with the sides of the slot on the fuel rail cup. This interference prevented further rotation during shipping.
Another method to prevent movement during shipping consisted of providing upright tangs biased towards the fuel rail cup and contacting the fuel rail cup. This method applied pressure to the sides of the fuel rail cup and prevented rotational movement of the fuel injector in relation to the fuel rail cup. This design was not compatible with certain materials used for fuel rails, especially composites and aluminum.
Other methods for preventing shifting during shipping for fuel rail cups formed from composites or aluminum were utilized. One method consisted of a retaining clip with protrusions directed towards the fuel rail. The fuel rail cup was expanded onto the sides of the fuel rail itself and a slot was defined on the side of the fuel rail. These protrusions were longer than the tangs and other protrusions described previously. A spring extended from one of these protrusions to contact the slot on the fuel rail to prevent shifting. However, this method did not significantly prevent axial rotation of the injector in relation to the fuel rail cup and since pressure was applied directly to the side of the fuel rail, certain materials could not be used to construct the fuel rail.
The above methods prevent damage to the fuel rail cup and the fuel injector that would be caused by large shifts during shipping. They also prevent the fuel injector from separating from the fuel rail cup. However, the fuel injector can still shift enough to affect alignment, and thus affect emissions and performance of the engine. It is desirable to prevent all shifting of the fuel injector in relation to the fuel rail cup during shipping in order to maintain the correct orientation of the fuel spray plume into the fuel intake. A retention method that accomplishes this would maintain its function even after shipping and reduce the need for repairs to the fuel injection system by preventing the injectors from becoming misaligned during both shipping and regular use.
The present invention provides a method and an apparatus for maintaining the alignment of a fuel injector during shipping and normal use. In one embodiment of the invention, a clip for retaining a fuel injector to a fuel rail cup that has an annular flange is provided. The clip has a base to at least partially surround an end of the fuel injector and a plurality of upstanding tangs to receive and substantially surround the annular flange. An alignment protrusion is also provided on the clip to interface with the annular flange to prevent axial rotation of the fuel injector relative to the fuel rail cup.
In another embodiment of the present invention, a retaining clip and fuel rail cup combination is provided comprising a fuel rail cup attached to a fuel rail and having an annular flange with at least one slot defined in it extending radially from the fuel rail cup. A retaining clip with a flat base, an open side and a plurality of tangs arranged to substantially surround and grip the annular flange is provided and at least one protrusion extends upwardly from the flat base of the clip to be received in the slot in the annular flange.
In yet another embodiment of the present invention, a method for maintaining the alignment of a fuel injector relative to a fuel rail cup having an annular flange is provided. The method comprises the steps of positioning inwardly biased tangs on a retaining clip to apply pressure to the sides of the annular flange and preventing the axial rotation of the fuel injector by utilizing an alignment protrusion to align with a slot in the annular flange and apply pressure to the sides of the annular flange.